The present invention relates to a chuck assembly for chucking a drill or the like.
FIG. 5 shows a conventional chuck assembly used for a router machining tool or the like. The chuck assembly is composed a spindle 22 provided with an opening portion 21, chucks 24 provided in the opening portion 21 for defining an opening portion for clamping a tool 20, and a sleeve 25 provided with a pressure member 28 for narrowing the opening portion 23 of the chucks 24. In the conventional example shown in FIG. 5, when the sleeve 25 is screwed and moved toward the right of FIG. 5, the tool 20 is clamped and fixed by the pressure of the pressure member 28.
By the way, in the clamping and fixing work of the tool 20 according to the conventional example shown in FIG. 5, for example, a wrench for holding the spindle 22 to be unrotatable and an operational jig for operatively rotating the sleeve 25 are prepared. The spindle 22 is prevented from rotating by being held with the wrench. The operational tool is retained at retainer recesses 26 of the sleeve 25. The sleeve 25 is rotated relative to the spindle 22. Accordingly, the worker has to hold the tool inserted into the opening portion 23 of the chucks 24 in addition to the wrench for preventing the rotation of the spindle 22 and the operational jig for rotating the sleeve 25. Thus, the tool clamping and fixing work is very troublesome. Incidentally, reference numeral 27 in FIG. 5 denotes a taper portion formed in an inner circumferential wall of the opening portion 21 of the spindle 22.
Also, another conventional example of a chuck assembly has been proposed in which a suitable lock mechanism is provided, and the sleeve is rotated after the rotation of the spindle is prevented by the operation of the lock mechanism.
In this conventional example, in the clamping and fixing work of the tool, it is unnecessary to manually hold the spindle due to the existence of the lock mechanism. Accordingly, in comparison with the conventional example shown in FIG. 5, the workability becomes better. However, the lock mechanism becomes intricate so that the cost therefor is high.